We consider a vehicular network where vehicles broadcast V2V messages with periodic and event-triggered, i.e., aperiodic, traffic.  A typical example of periodic traffic is the regular broadcast of vehicle information such as position and speed, as in cooperative awareness messages (CAMs) [1]}, whereas aperiodic traffic is triggered on events to warn vehicles such as of an accident, as in decentralized environmental notification messages (DENMs) [2]}. The V2V messages are assumed to have a fixed size of \(S\textsubscript {msg}\) , requiring a predefined number of time-frequency resources based on the modulation and coding scheme (MCS). In the case of the periodic traffic, the messages are generated with a fixed periodicity of \(T\textsubscript {msg}\)  by all vehicles. For the event-triggered traffic, the event arrivals are assumed to follow a Poisson process with an arrival rate of \(X\textsubscript {evt}\)  per s for each vehicle [3]}, upon which a single message is generated.According to the ETSI specifications [1]}, [2]}, while periodic by default, the periodicity of CAM transmissions can be adjusted depending on vehicular mobility and traffic load, and DENM transmissions might contain bursts of several periodic messages. We evaluate the impact of the different modes of traffic separately, by following previous research work (e.g., [6]}, [7]}) and applying the traffic models proposed in 3GPP [3]}. This approach makes the analysis easier and enables us to generalize our results to any type of V2V traffic beyond the CAM and DENM applications.
